patch for bug #9806

Sam Liddicott sam at liddicott.com
Thu Apr 18 11:12:32 MDT 2013


Attached is a patch I'm working on for bug #9806
https://bugzilla.samba.org/show_bug.cgi?id=9806

It is not final, but serves as a talking point - it does not address the
root cause yet, but rather restarts task services that crash.

I now understand Jelmer's point on IRC that restarting a crashed service
was not a goal; for the distribution of structs and config data available
in service.c, service_task.c and process_standard.c meant that there was no
neat way to detect a crashed service and properly restart it from a point
that should be aware that service tasks were processes.

Really only process_standard.c could care about this and I was able to get
it to detect crashed processes and attempt to restart, but even though I
called the new_task callback the old information was left
in /var/lib/samba/private/smbd.tmp/msg/names.tdb  - or so I imagine,
certainly processes attempted to connect to the old pipe.

perhaps task_terminate should have been called but the proper information
to do that is not available in process_standard.c

Service_task.c routines do have the information but can't really be
informed about a processes demise or provided with the right information to
restart it. I could add to service.c some function to restart a server
service; but in the end I settled for a simpler model where
process_standard.c would spawn a child whose only purpose was to re-spawn
the service process which would operate using the pid of it's monitoring
parent. This meant that the pipes used for communication would retain the
same name which I think is an advantage.

I acknowledge that the real issue should be addressed, but feel that
avoiding user curses gets a high priority and this addresses that.

I do acknowledge that the winbind task when run in the standard process
model DOES fork children to deal with each connection, but yet it also will
crash in the manner outlined in the bugreport when port 88 is blackholed.

Sam
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